The present invention relates to an apparatus and method for field burning and fog or smog control. The successful cultivation of certain agricultural crops, for example grass seed, requires that after each season's crop has been harvested and before the next season's crop may be planted the land on which the crop is produced must be sterilized and decontaminated by removing all residual vegetation, seeds and vermin. The predominant method of sterilizing the land is by openly burning the vegetation from the field where it lies. This open burning creates a strong updraft of hot, expanding gases which carries a large quantity of incompletely combusted particulate matter into the atmosphere over the area being cleared. Due to the rapid expansion and resultant cooling of these gases, the particulate matter is dispersed into the atmosphere at a relatively low altitude where it is picked up and carried by the prevailing winds. All to often this low-altitude airborne matter is carried over urban centers where it decreases visibility and creates a hazard to the health of the urban populace. Investigation is being conducted into ways of sterilizing agricultural lands by non-polluting combustion, for example by the use of mobile field burning machines which traverse the ground and burn the vegetation within small controlled combustion chambers. However, such mobile machines are of far too small a capacity and much too expensive to make their use over large acreages economically feasible. Moreover, they too disperse the hot combustion gases, together with unburned particulate matter, at an unsatisfactorily low altitude. In addition, while such mobile field-burning machines are small in comparison to the large acreages they are expected to cover, they are generally too large for convenient road haulage from job to job. Accordingly, to date no acceptable non-polluting means of accomplishing soil sterilization by burning has been discovered.
A similar menace to urban population is created by a condition known as smog, that is, smoke or other pollutants mixed with fog. Normally, the tempeprature of the atmosphere below the stratosphere decreases with altitude with the warmer air near ground level continually rising until its temperature drops to that of the surrounding air. Whenever this air temperature relationship is reversed, such as when a cool stable air mass is trapped over a large area by a similarly stable and relatively warmer air mass overhead (a condition known as a temperature inversion), the rising air currents necessary to mix the polluted air from the lower altitudes with the relatively cooler and clearer air of the higher altitudes are suppressed. This causes the cool, stable air to remain adjacent the ground for considerable periods of time and results in the accumulation of a high concentration of smoke and other pollutants in the air, decreasing visibility and endangering the health of the animal and plant life living within the area. It is not uncommon for these temperature inversions and the resultant accumulations of airborne pollutants to remain in an area for a matter of days or weeks until dispersed by wind or by changes in the temperatures of the respective air masses. To date, no means has been devised to effectively speed up the natural removal of fog or smog from large areas.